Placement method of an electronic module on a substrate and device produced by said method

ABSTRACT

The aim the disclosed process is to ensure maximum precision both at the level of the manufacturing of an electronic assembly from a chip with small dimensions as well as the level of the placement of such an assembly on an insulating substrate. This aim is achieved by a placement process on a support, called substrate, of at least one electronic assembly consisting of a chip including at least one electric contact on one of its faces, said contact being connected to a segment of conductive track, and said placement being carried out by means of a placement device holding and positioning said assembly on the substrate, comprising the following steps:
         formation of a segment of conductive track having a predetermined outline,   transfer of the track segment onto the placement device,   seizing of the chip with the placement device carrying the track segment in such a way that said track segment is placed on at least one contact of the chip.   placement of the electronic assembly consisting of the chip and the track segment at a predetermined position on the substrate,   embedding of the chip and of the track segment into the substrate.       

     A placement device used in the process and a portable object including an electronic assembly placed according to the process are also objects of the present invention.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No. 11/342,911filed Jan. 30, 2006, now U.S. Pat. No. 7,785,932, issued Aug. 31, 2010,claiming priority from EP05100694.8 filed Feb. 1, 2005 and EP05109094.2filed Sep. 30, 2005. All of the above mentioned applications beingincorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention concerns the field of assembly of transponders,chip cards, integrated circuits or other digital data support and moreparticularly the placement, mounting and connection of electronicassemblies on an insulating support, more commonly known as a substrate.

PRIOR ART

An electronic assembly means here a component in the form of asemi-conductive chip, provided on one of its faces with electric contactareas on which segments of conductive tracks are arranged for extendingsaid contacts. These segments of track are connections linking the chipto external elements located on the substrate. For example, in atransponder, the track segments of the assembly are used for connectingit to the ends of an antenna arranged on the perimeter of the substrate.

There are several processes of placement and connection of a chip or anelectronic assembly on a substrate including conductive tracks, namely.

The document EP0694871 describes a placement process of a chip carriedout by means of a hot-pressing tool. The tool seizes the chip, with theface including the contacts directed upward, and then hot presses itinto the substrate material. The face including the contacts is levelwith the surface of the substrate. The connections are produced usingsilk-screen printing or by track tracing by means of conductive ink thatconnects the contacts of the chip to an antenna, for example. Accordingto an embodiment, a track segment is placed on the substrate and thechip is hot pressed with the face carrying the contacts directed towardsthe substrate in order to make a connection by pressing a contact ofsaid chip on the track segment.

In the document WO98/26372, the chip includes contacts in relief and itis placed with the face carrying the contacts directed towards thesubstrate. The contacts of the chip are applied against conductiveterminals of an antenna printed on the substrate. An intermediateplastic sheet is superimposed on the substrate equipped in this way andcovers the chip. A second sheet covers the substrate before the hotlamination of this assembly of sheets. This process called the “flipchip” technique allows the placement and the connection of the chip tobe carried out in one single operation and guarantees the minimalthickness of the assembly.

The document WO98/44452 describes a manufacturing process of a chip cardcomprising at least one microcircuit in the substrate of the card. Themicrocircuit is positioned in such a way that the output studs aredirected upwards. Applying conductive ink with a syringe carries out theconnection of the studs with the contacts of an antenna placed on thesurface of the substrate. The microcircuit is placed at the bottom of acavity that has a greater depth than the thickness of the microcircuitin order to leave a space that allows said microcircuit to be coveredwith resin after the connections have been carried out. The connectionsfollow the profile of the microcircuit and the one of the cavity beforereaching the contacts or tracks printed on the surface of the substrate.

In the process described in the document EP1410322, a complete modulecomprising a chip provided with contact areas is placed from a supportstrip on a substrate, including the printed conductive tracks, alsoarranged on a strip. A module among those fixed on the strip is placedface to a part of strip equipped with an assembly of conductive tracksthat form, for example, an antenna. Then, it is separated from the stripin order to be adhered onto the substrate in the proximity of theterminals of the antenna. The connection of the contact areas of themodule to the antenna is carried out by pressure and crimping with asuitable device during the gluing of the module.

The document FR2780534 describes a manufacturing process of an objectincluding a body comprising a semi-conductive chip provided with contactareas on one of its faces and metallizations forming an antenna. Theprocess consists in inserting the chip by hot pressing into a smallboard made of thermoplastic material. The face of the chip provided withcontact areas is placed in such a way that it is level with one of theface of the board. The metallizations forming the antenna as well as theconnections of the contact areas of the chip are made on the same faceof the board by silk-screen printing of conductive ink.

This process becomes inapplicable when the dimensions of thesemi-conductive chip are very small, of approximately a few tenths of amillimeter. In fact, silk-screening or the application of conductivematerial by another process (tracing, projection) does not allow thenecessary precision to be achieved that prevents short circuits or thebreaking of contacts at the level of the connection areas on the chip.

The main drawback of the aforementioned placement and connectionprocesses is their lack of precision, especially when the dimensions ofthe chip forming the electronic assembly are notably reduced, forexample 0.2 mm by 0.2 mm. Furthermore, the very small distance, ofapproximately 0.05 mm, that separates the track segments attached to thecontacts of the chip, requires a high level of precision in terms ofpositioning and connection.

In the three first examples, only a chip or a microcircuit is placed onthe substrate either with the contacts pressed on the tracks printed onone face of the substrate (flip-chip), or with the visible contactsconnected subsequently. These two types of processes become ratherunreliable when the size of the chip and the contacts reduces.

In the penultimate example, the modules are manufactured separately andarranged on a strip before being placed on the substrate. This processis also relatively slow and expensive.

SUMMARY OF THE INVENTION

The aim of the present invention is to ensure maximum precision both atthe level of manufacturing an electronic assembly from a chip with smalldimensions as well as at the level of the placement of this type ofassembly on an insulating substrate. Another aim is to achieve a verylow transponder production cost with a high manufacturing rate.

These aims are achieved by a placement process on a support, calledsubstrate, of at least one electronic assembly consisting of a chipincluding at least one electric contact on one of its faces, saidcontact being connected to a segment of conductive track, and saidplacement being carried out by means of a placement device holding andpositioning said assembly on the substrate, comprising the followingsteps:

-   -   formation of a segment of conductive track having a        predetermined outline,    -   transfer of the track segment onto the placement device,    -   seizing of the chip with the placement device carrying the track        segment in such a way that said track segment is placed on at        least one contact of the chip.    -   placement of the electronic assembly consisting of the chip and        the track segment at a predetermined position on the substrate,    -   embedding of the chip and of the track segment into the        substrate.

The term substrate here refers to any type of insulating support whetherit is a card, a label, an object or a part of the structure of theobject (apparatus shell, identification badge, box, package lining,document, etc.) likely to be equipped with an electronic assemblyaccording to the process above.

According to a preferred embodiment, the track segment consists of athin strip of any shape stamped from a sheet of conductive material witha stamping tool. It is then transferred onto the positioning device thatholds it, for example, by means of an air suction device. In general,the number of stamped track segments corresponds to the number ofcontacts of the chip. They are held by the positioning device accordingto an arrangement depending on the positions of the contacts on thechip. Their shape and their individual dimensions are also determined bythe configuration of the chip contacts as well as by the one of theconductive tracks of the substrate.

The track segments can also form a transponder antenna that works, forexample in the domain of UHF frequencies (Ultra High Frequency). In onecase, the end of the segment that is not connected to the chip remainsfree, that is to say without connection to other tracks on thesubstrate. According to another configuration, the segment forms a loop,with each end connected to the chip. Of course, the placing device canhandle such a segment in the same way as a segment including only oneend connected to the chip.

In this type of configuration, it is possible that the chip may includeother contacts from which segments are connected to tracks or to contactsurfaces arranged on the substrate.

The placement device whereon the track segments are fixed seizes a chip,also by means of suction according to one embodiment, the ends of thetrack segments being applied against the chip contacts. This assembly isthen positioned and pressed on the foreseen place on the substrate andthe free ends of the track segments connect to the terminals of acircuit present on the substrate (for example, an antenna).

The aim of this invention also consists in a placement device intendedfor positioning an electronic assembly on a substrate, said assemblycomprising a chip provided with at least one electric contact connectedto a conductive track segment, said device provided with means forpositioning and pressing the electronic assembly onto the substratecomprises a head equipped with means for maintaining of at least oneconductive track segment, and said maintenance means being connected toseizing and means for holding a chip so that the track segment isconnected to at least one contact of the chip.

The means for holding the track segment are preferably made up of an airsuction device that creates a vacuum on one of the faces of the tracksegment. A similar device can be also provided to pick up a chip withone end of the track segment being applied against a contact of thechip. The assembly thus mounted is transported towards a predeterminedlocation on the substrate where it will be implanted. The placementdevice also includes means for pressing the assembly into the substrate.

One advantage of the invention is to avoid the production of anintermediate module due to the fact that the electronic assembly isassembled by means of the placement device before it is placed on thesubstrate.

The invention also refers to a portable object comprising on all or partof its structure an insulating substrate in which at least oneelectronic chip is embedded, said chip includes a face having at leastone contact and said face is placed at the same level as the surface ofthe substrate, wherein at least one conductive track segment appliedagainst the surface of the substrate is connected to the contact of thechip.

DESCRIPTION OF THE DRAWINGS

The invention will be better understood thanks to the detailed followingdescription that refers to enclosed drawings, which are given as annon-limitative examples, in which:

FIG. 1 shows the stamping of the track segments from a strip ofconductive material and a transparent schematic top view of theplacement device holding a chip and the track segments.

FIG. 2 shows an enlarged section view of the electronic assemblyconsisting of the chip and the track segments.

FIG. 3 shows a top view of a part of substrate where the assembly isplaced and connected to printed tracks.

FIG. 4 shows an enlarged section view of the part of the substrate inFIG. 3.

FIG. 5 shows a schematic bottom view of the head of the placement deviceholding the track segments and the chip.

FIG. 6 shows an embodiment where the track segments are stamped from aconductive strip provided with insulating areas.

FIG. 7 shows a top view f of a part of the substrate where the tracksegments of the assembly provided with insulating areas cross and/orsuperimpose other tracks of the substrate.

FIG. 8 shows a top view of a part of the substrate where the tracksegments of the assembly are longer and provided with insulating areas.They are adhered onto the substrate and cross the tracks.

FIG. 9 shows an enlarged section view of a part of the substrate wherethe chip-segments assembly is embedded in the substrate.

FIG. 10 shows an enlarged section view of a part of substrate includinga cavity with dimensions larger than those of the chip, thechip-segments assembly is held in the cavity thanks to an adhesive thatfills the free spaces.

FIG. 11 shows an enlarged section view of a part of a substrateincluding a cavity with a depth lower than the height of the chip. Thesubstrate material fills the free spaces during the embedding of thechip-segments assembly into the cavity.

FIG. 12 shows an enlarged section view of a part of the substrate formedby two superimposed layers, the upper layer includes a window withdimensions approximately equal to those of the chip, the chip-segmentsassembly being embedded in the window.

FIG. 13 shows an enlarged section view of a part of the substrate formedby two superimposed layers, the upper layer includes a window withlarger dimensions than those of the chip, the chip-segments assembly isheld in the cavity thanks to an adhesive that fills the free spaces.

FIG. 14 shows an enlarged section view of a part of a substrate formedby two superimposed layers, the upper layer having a thickness lowerthan the height of the chip includes a window. The material of the lowerlayer of the substrate fills the free spaces during the embedding of thechip-segments assembly into the window.

FIG. 15 shows an enlarged section view of a part of the substrate formedby two superimposed layers, the lower layer includes a window. Thechip-segments assembly is embedded into the upper layer facing thewindow of the lower layer.

FIG. 16 shows the section view in FIG. 15 with the chip-segmentsassembly embedded in the upper layer and the material of said layerfills the window of the lower layer.

FIG. 17 shows a part of the substrate comprising a chip-segmentsassembly with segments crossing the conductive tracks by passing overinsulating segments.

DETAILED DESCRIPTION OF THE INVENTION

According to the process of the invention, each electronic assembly ismounted before its placement and connection with other elements presenton the substrate. The track segments (3, 3′), which number usuallycorresponds to the number of contacts (5, 5′) of the chip (4), are cutfrom a sheet (2) of conductive material and are then assembled on thesecontacts (5, 5′).

FIG. 1 shows an example of a pair of rectangular track segments (3, 3′)arranged in a staggered way stamped in a sheet (2) or a copper striporiginating from a roll, for example. The stamping tool (1) operateshere from bottom to top and pushes the cut segments (3, 3′) towards itsupper surface in such a way as to be transferred easily onto theplacement device (6). The latter is placed above the stamping tool (1)and sucks the segments (3, 3′) up by holding them in the same positionthan during stamping. An electronic chip (4) is then seized by theplacement device (6) that carries the segments (3, 3′) in such a waythat its contacts (5, 5′) touch the nearest ends of each segment (3, 3′)in a central area of the head of the placement device (6). The chip (4)is also held on the device by suction in a similar way to track segments(3, 3′).

The assembly thus formed held by the placement device (6) is thenpositioned and subsequently hot pressed, for example, into a substrate(7) by the same device. The contact surface of the assembly that isdirected upwards is level with the surface of the substrate (7) as shownin the section view of FIG. 4 and the track segments (3, 3′) are placedflat against the surface of the substrate (7).

The free ends of the segments (3, 3′) are connected by exerting pressureon the appropriate terminals which are formed with conductive tracks (8,8′) arranged on the substrate (7), see FIG. 3.

In a final step of the assembly, an insulating protection sheet (9) islaminated, according to a known technique, on all or part of the surfaceof the substrate (7) ensuring the final mechanical holding of theelectronic assembly made up of the track segments (3, 3′) and the chip(4), the electric connections having been made previously.

This placement process is applied advantageously, for example, duringthe manufacturing of transponders or of contactless chip cards where theelectronic assembly is connected, for example, to the ends of anantenna.

FIG. 2 shows the section view of an assembly consisting of a chip (4)comprising two contacts (5, 5′) each provided with a bump. Theconnection of the track segments (3, 3′) is carried out by exertingpressure in such a way that the bumps achieve the electric contact withthe conductive material of the segment. The bumps can also be made of aconductive material that is fusible at a relatively low temperature (tinbased alloy, for example) so that the placement device carries out theconnection of the track segments with heat supply.

When the melting point of the bumps material is higher, such as forexample in the case of gold, an optimal electric contact is ensured bysupplementary weld spots, for example by laser, ultrasound or also bythermo-compression. These welding operations can be carried out eitherwith the placement device during or after the embedding of theelectronic assembly in the substrate (7) or during a supplementary stepafter the placement of the electronic assembly. Another possibilityconsists in using a welding device separate from the placement device inorder to weld, during a previous step, the conductive segment(s) (3, 3′)with the contacts (5, 5′) of the chip (4) at a high temperature. Thechip-segments assembly is then transferred onto the placement devicethat places said assembly on the substrate (7) for embedding it at alower temperature adapted to the softening of the substrate, forexample. Due to the high temperature of the welding device, thisplacement operation becomes difficult to carry out with only one deviceexecuting both the welding and the placement without damaging thesubstrate.

According to an embodiment, the connection of the track segments (3, 3′)on the contacts (5, 5′) of the chip (4) can be carried out through theapplication of a conductive adhesive on these contacts (5, 5′) beforethe placement device (6 seizes the chip (4). Another possibilityconsists in applying the conductive adhesive to the end of the segments(3, 3′) facing the contacts (5, 5′) of the chip (4). This operation iscarried out during a step prior to the transfer of the segment (3, 3′)onto the placement device (6) before or after its stamping. The adhesivecan also be applied previously in an inactive form on the conductivesheet and then subsequently activated. The adhesion of the contacts (5,5′) of the chip (4) with the track segments (3, 3′) is thus carried outduring the seizing of the chip (4) by the placement device (6) thenduring or after the embedding step of the chip-segments assembly intothe substrate (7).

FIG. 5 represents a schematic bottom view of the head of the placementdevice (6) according to the invention provided with openings (10, 10′,11) intended to hold, by means of air suction (vacuum), the differentelements of the electronic assembly. In a first step, the air suctionthrough the openings (10, 10′) allows the reception of the tracksegments (3, 3′) on the stamping tool (1) and holds them and inposition. In a second step, the chip (4) is seized from a suitablesupport also by means of air suction through a central orifice (11). Theelectronic assembly built in this way and held by the placement deviceis finally transported towards the location provided on the substrate(7) and pressed into the material. The head of the placement device (6)can be made up of either several pieces assembled together or of onlyone block providing a global support to the stamping tool, to thesuction system of the segments and the chip, to the welding means etc.according to one example of configuration.

FIG. 6 shows an embodiment wherein the conductive strip (2) on which thetrack segments (3, 3′) are stamped is provided with insulating areas(12, 12′) applied against the lower face of the strip. These areas (12,12′) are arranged in order to form a central insulated part (13, 13′),on the face that will be applied against the substrate, of each segmentstamped from this strip (2). The ends of the segments (3, 3′) arereleased from the insulating area in order to ensure the connectionswith the chip (4) and the conductive tracks or areas of the substrate(7) provided for that purpose. This isolation prevents short-circuitswith the tracks (8, 8′) of the substrate (7) that the segments cross incertain configurations, as shown in FIG. 7.

According to one embodiment, the insulating areas on the segments can becarried out from insulating segments obtained in a similar way to theconductive segments, but from an insulating film. These segments aretransferred onto the placement device on which they are held against theappropriate track segments before the placement and embedding of theassembly in the substrate. This alternative allows the production ofinsulating segments of any shape and namely wider than the conductivesegments in order to ensure improved isolation of a track crossing, forexample (see the example in FIG. 17)

According to another embodiment shown in FIG. 8, and in case thesegments (3, 3′) are longer, the insulating film of the conductive strip(2) can comprise an adhesive layer. The adhesive, once activated,ensures the holding of the segment on the substrate when it crossesseveral tracks, for example. The adhesive layer can also be arranged onthe substrate (7) instead of being applied on the insulating film.

During the placement of the assembly, the segments (3, 3′) are adheredonto the substrate (7), for example, thanks to the activation bylocalized heating of the adhesive layer by the placement device (6) atpoints (14, 14′) facing the insulating area. These points (14, 14′) arepreferably situated outside the tracks of the substrate (7) thusallowing improved adhesion.

According to one embodiment, the same device carries out the stampingoperations of the segments (3, 3′) of conductive tracks and theplacement of the assembly. In this case, the head of the device iscompleted with a stamp for cutting out the track segments (3, 3′). Awithdrawal of the stamp allows the suction openings (10μ, 10′) to holdthe segments (3, 3′) in a suitable position before the seizing of thechip (4). The transfer step of the track segments (3, 3′) from thestamping tool towards the placement device is therefore eliminated.

According to another embodiment, the means for seizing and holding thechip comprise adhesive elements that replace the opening(s) (11) in thecentral area of the placement device (6). The chip (4) is thereforeadhered temporarily between its contacts (5, 5′) during the transport ofthe electronic assembly towards its location on the substrate (7). Theadhesive elements have a weaker adhesive force than that of the fixingof the chip (4) on the substrate (7) in order to allow the withdrawal ofthe placement device (6) after the embedding of the electronic assembly.The adhesive can remain on the chip (4) after having been placed withthe aim of improving the flatness of the surface of the electronicassembly in case the chip (4) includes contacts (5, 5′) with bumps.

It should be noted that adhesive elements conductive according to avertical axis (axis Z) can also be added onto the placement device (6)facing the contacts of the chip (4). These elements can either replacethe adhesive elements or the suction opening(s) (vacuum) of the centralarea, or complete them.

According to a further embodiment, the head of the placement device (6)can include means for welding the track segments (3, 3′) onto thecontacts of the chip (4). These welding means consist of, for example, alaser or ultrasonic source or one or several heat elements. In general,they are activated before or during the placement or during or after theembedding of the electronic assembly in the substrate (7) in order toexert the necessary pressure on the elements to be welded.

The process according to the invention also applies to the manufacturingof smart cards or transponders comprising substrate that is notthermo-fusible, namely a substrate that will not melt or soften when thetemperature is raised. The substrate can be made up of a material basedon cellulose such as paper or cardboard. In this case, it is preferableto create a cavity in which the chip will be placed provided with itstrack segments. The cavity can be executed by milling or embedding of adie after the previous softening of the substrate with solvents with orwithout elevation of the temperature. The electronic assembly can alsobe cold or hot pressed directly into the material that is locallydeformed or in an area made malleable in order to absorb the volume ofthe chip. The aim of the process, as in the case of thermo-fusiblesubstrates, is to preserve precise positioning without clearance, whichmeans without possibility of movement of the assembly inside the cavity.Of course, such a cavity for cavity the chip can also be formed in athermo-fusible substrate whereon localized heating can facilitate theembedding and the holding of the chip in the cavity.

Tests with certain non thermo-fusible substrates have shown that adirect embedding process using hot pressing of the assembly can causethe combustion of the material of the substrate at the position of thechip, creating thus the cavity. In this case, the previous formation ofthe cavity is no longer necessary.

Several embodiments of the process disclosed in FIGS. 9 to 14 can bepresented according to the material or the structure of the substrate oraccording to the equipment available, namely:

-   -   FIG. 9 shows the simplest embodiment in which the chip-segments        assembly is directly embedded in the material of the substrate        (7) either hot or cold with providing solvents. In certain        cases, in order to facilitate the placement of the assembly, a        cavity (15) is formed in the substrate (7) with dimensions that        are slightly smaller or equal to those of the chip (4). The        depth of the cavity (15) corresponds approximately to the        thickness of the chip (4) so that the face including the        segments (3, 3′) is level with the surface of the substrate (7).        This cavity (15) is preferably created during a step prior to        the placement of the chip-segments assembly with the placement        device (6). The latter embeds or inserts the assembly into the        cavity (15) in which it is held thanks to the similarity of the        dimensions of the cavity (15) and the chip (4). In order to        reduce the embedding pressure, it is also possible to soften        locally the periphery of the cavity (15) with appropriate        solvents.    -   FIG. 10 shows the case in which the dimensions of the cavity        (15) are larger than those of the chip (4) with a depth        corresponding approximately to the thickness of the chip (4). In        this case a substance, preferably adhesive (16), such as for        example, a thermo-fusible, thermo-hardening, or ultra-violet        light photo-hardening resin or any other suitable adhesive, is        applied into the cavity (15). The placement device (6) then        embeds the chip (4) in the adhesive substance (16) that is        distributed and discharged into the free space left along the        outline of the chip (4). This filling allows the holding of the        chip-segments assembly in a stable position after the hardening        of the adhesive substance (16).    -   FIG. 11 shows the case wherein the depth of the cavity (15) is        lower than the thickness of the chip (4) and with dimensions        that are larger than those of the chip (4). The placement device        (6) embeds the chip so that the face of the chip (4) including        the segments (3, 3′) is level with the surface of the substrate        (7). In order to ensure leveling without excessive deformation        of the substrate (7), the latter can be softened (solvents or        heating) at the level of the cavity (15) also allowing the        discharge (17) of the material of the substrate (7) in the free        space surrounding the chip (4). This space filled in this way        holds the position of the chip-segments assembly in the cavity        (15).    -   This embodiment of the process can be combined with the previous        one by adding an adhesive substance (16) in the cavity disclosed        in FIG. 11 in order to complete the filling of the space        according to the dimensions of this cavity (15) compared to        those of the chip (4).

FIGS. 12 to 14 show one embodiment in which the substrate (7) is formedby two superimposed layers (7′, 7″) placed one on top of the other. Theupper layer (7′) includes a window (18), namely a perforation throughthe entire thickness of this layer (7′). In general, the window (18) iscarried out by stamping the upper layer (7′) of the substrate before theplacement of the lower layer (7″). The lower face of the window (18) isclosed with the lower layer (7″) of the substrate (7) in order to form acavity holding the chip (4) in an accurate position. The laminating ofboth layers of the substrate is carried out during a subsequent stepafter the placement of the electronic assembly in the cavity.

-   -   FIG. 12 shows the embodiment wherein the dimensions of the        window (18) are smaller or equal to those of the chip (4) and        the thickness of this layer (7′) is equivalent to that of the        chip (4). As in the embodiment in FIG. 9, the chip (4) is        embedded in the window (18) and is held directly by the walls of        the window (18). The face of the chip (4) including the segments        (3, 3′) is level with the surface of the upper layer (7′) of the        substrate (7).    -   FIG. 13 shows the embodiment wherein the dimensions of the        window (18) are larger than those of the chip (4) and the        thickness of the upper layer (7′) corresponds approximately to        that of the chip (4). As in the embodiment in FIG. 10, an        adhesive substance (16) is applied in the cavity formed by the        window (18) in order to fill the space surrounding the chip (4)        when the latter is placed in window (18) and embedded in        adhesive substance (16).

The embodiments of FIGS. 12 and 13, wherein the thickness of thesubstrate including the window is similar to that of the chip, can alsobe presented without the lower substrate. The chip is held either by theedges of the window or by an adhesive substance that fills the spacebetween the edges of the window and the chip. Supplementary protectionlayers can also be added to the substrate during further steps in orderto cover one or both faces of the window.

-   -   FIG. 14 shows the embodiment wherein the thickness of the upper        layer (7′) of the substrate is smaller than that of the chip (4)        with the dimensions of the window (18) being larger than those        of the chip (4). In this case, as in that of FIG. 11, the chip        (4) is embedded across the window (18) and then in the lower        layer (7″) of the substrate (7) that is softened in such a way        as to discharge the material (17) of this layer (7″) along the        outline of the chip (4). The space filled in this way around the        chip (4) allows the latter to be held in the window (18).    -   Similarly to the embodiments of FIGS. 10 and 11, the embodiments        of FIGS. 13 and 14 can be combined. An adhesive substance (16)        can be added in the cavity shown in FIG. 14 in order to complete        the filling of the free space around the chip (4) according to        the dimensions of the latter compared to those of the window        (18).    -   FIGS. 15 and 16 show embodiments with a substrate (7) in two        layers where the window (18) is cut into the lower layer (7″) of        the substrate (7). The assembly of chip (4) segments (3, 3′) is        embedded in the upper layer (7′) facing to the window (18) of        the lower layer (7″) with the placement device (6). The pressure        exerted by the placement device (6) allows the softened material        of the upper layer (7′) to be discharged into the window (18) as        shown in FIG. 16. The segments (3, 3′) are level with the        surface of the upper layer (7′) as in the embodiments in FIGS. 9        to 14.

The dimensions of the window (18) and the thickness of the layers (7′,7″) of the substrate (7) are also determined by the volume of materialnecessary to fill the window without allowing the appearance, on thesurface of the substrate (7), of a depression or a bump which could harmthe application of the assembly of chip (4) segments (3, 3′) integratedinto the substrate (7).

FIG. 17 shows an example of an embodiment carried out according to theprocess of this invention. The part of the substrate (7) includes a chip(4) provided with contacts (5, 5) each connected to one end of aconductive segment (3, 3′). The other end of each conductive segment (3,3′) is connected to conductive tracks (21, 21′) arranged on thesubstrate (7). The first segment (3′) originating from the chip crossesa set of conductive tracks (21) passing over a first insulating segment(20′). The second conductive segment (3) of the chip (4) is connected onone end of a track (21′). This track (21′) is connected to a thirdconductive segment (3″) leading to a distant track (21″) passing over asecond insulating segment (20) covering a set of tracks (21).

The placement process of these different elements (conductive,insulating segments and chip) is summarized as follows:

-   -   stamping of the three conductive segments (3, 3′, 3″) and        seizing by the placement device (6),    -   stamping of two insulating segments (20, 20′) and seizing by the        placement device (6),    -   seizing of the chip (4) so that its contacts (5, 5′) face the        ends of the conductive segments (3, 3′) previously seized and to        which ends they will be connected during the step of embedding        into the substrate (7).    -   placement in a predetermined position on the substrate (7) and        embedding of all the seized elements in such a way that the face        of the chip including the contacts as well as the conductive and        insulating segments are level with the surface of the substrate.

1. An electronic assembly being configured to be embedded as a whole bya placement device into a portable object comprising an insulatingsubstrate, said electronic assembly comprising an electronic chip havingat least one contact on a face and at least one conductive track segmentelectrically connected to said at least one contact, wherein the chipbeing configured to show the face having the at least one contactflushing with a surface portion of the insulating substrate, such thatthe entire embedded surface of the chip is in physical contact with theinsulating substrate, and said conductive track segment being configuredto be placed flat on the surface portion of said insulating substrate.2. The electronic assembly according to claim 1, wherein a weld spotensures the electrical connection between said one contact of theelectronic chip and said one conductive track segment.
 3. The electronicassembly according to claim 2, wherein the weld spot is made up of metalforming said one contact of the electronic chip melted together withmetal from said one conductive track segment.
 4. The electronic assemblyaccording to claim 1, wherein said one conductive track segment iselectrically connected to said one contact by a conductive adhesive. 5.The electronic assembly according to claim 1, wherein said oneconductive track segment is electrically connected to said one contactof the electronic chip at an end of said conductive track segment,another end of said conductive track segment remaining free.
 6. Theelectronic assembly according to claim 1, wherein said electronic chiphas at least two contacts on one of its faces and at least two separateconductive track segments each having an end electrically connected to adifferent contact among said at least two contacts.
 7. The electronicassembly according to claim 6, wherein said two conductive tracksegments each extend substantially parallel to the face of theelectronic chip, both conductive track segments being configured to forman ultra high frequencies transponder antenna.
 8. The electronicassembly according to claim 1, wherein the conductive track segmentforms a loop having an end electrically connected to said one contact ofthe electronic chip and the other end of said loop being electricallyconnected to another contact of the chip located on said face, said loopforming a transponder antenna.
 9. The electronic assembly according toclaim 1, wherein said electronic chip has a plurality of contacts onsaid face and a plurality of conductive track segments each electricallyconnected to a corresponding contact of said plurality of contacts. 10.The electronic assembly according to claim 9, wherein each conductivetrack segment is electrically connected to a corresponding contact ofthe electronic chip at an end of said conductive track segment, theother end remaining free.
 11. The electronic assembly according to claim10, wherein each conductive track segment extends separately from saidcorresponding contact of the electronic chip and parallel to said faceof said electronic chip, the plurality of conductive tracks segmentsbeing configured to form electrical links from said plurality ofcontacts towards respective terminals defined by conductive tracksarranged on an insulating substrate forming said portable object. 12.The electronic assembly according to claim 1, wherein said oneconductive track segment consists of a strip of conductive material. 13.The electronic assembly according to claim 6, wherein said plurality ofconductive track segments consist each of a strip of conductivematerial.
 14. The electronic assembly according to claim 9, wherein saidplurality of conductive track segments consist each of a strip ofconductive material.
 15. The electronic assembly according to claim 1,wherein said one conductive track segment consists of a copper strip.16. The electronic assembly according to claim 6, wherein said at leasttwo separate conductive track segments consist each of a copper strip.17. The electronic assembly according to claim 9, wherein said pluralityof conductive track segments consist each of a copper strip.
 18. Theelectronic assembly according to claim 1, wherein said one conductivetrack segment is provided with an insulating area located in a centralpart of said conductive track segment for forming an insulated part, inorder to isolate the conductive track segment from conductive tracksarranged on an insulating substrate forming said portable object andthus to prevent short-circuits with these conductive tracks when theelectronic assembly is further assembled with said insulating substrateto form the portable object.
 19. The electronic assembly according toclaim 18, wherein said insulating area is formed by an insulatingsegment applied against said one conductive track segment.
 20. Theelectronic assembly according to claim 19, wherein said insulatingsegment comprises an adhesive film.
 21. Portable object comprising aninsulating substrate and an electronic assembly which is configured tobe embedded by a placement device as a whole in said insulatingsubstrate, wherein said electronic assembly comprises an electronic chiphaving at least one contact on a face and at least one conductive tracksegment electrically connected to said at least one contact, said faceof the chip having the at least one contact flushes with a surfaceportion of the insulating substrate, such that the entire embeddedsurface of the chip is in physical contact with the insulatingsubstrate, the at least one conductive track segment having a first endelectrically connected to said at least one contact is placedsubstantially flat on said surface portion of said insulating substrate.22. Portable object according to claim 21, wherein said one conductivetrack segment has a second end electrically connected to a terminaldefined by a conductive track arranged on said surface of saidinsulating substrate.
 23. Portable object according to claim 22, whereinan insulating area is provided between a central part of said oneconductive track segment and said insulating substrate which compriseson said surface further conductive tracks which are crossed by said oneconductive track segment, in order to isolate said conductive tracksegment from said further conductive tracks and thus to preventshort-circuits with these further conductive tracks.
 24. Portable objectaccording to claim 21, wherein said electronic chip has at least twocontacts on one of its faces and at least two separate conductive tracksegments each having an first end electrically connected to a differentcontact among said at least two contacts and a second end electricallyconnected to a different terminal arranged on said insulating substrate,the conductive tracks segments being configured to form electrical linksfrom said at least two contacts towards respective conductive tracksarranged on said surface of the insulating substrate.
 25. Portableobject according to claim 24, wherein the separate conductive tracksegments each consist of a strip of conductive material.
 26. Portableobject according to claim 24, wherein the separate conductive tracksegments each consist of a copper strip.